276 TRANSACTIONS OF THE NORTHERN 



tive Committee of the State Society, to the form of bill that should be 

 presented to the Legislature. 



Mr. T. McWhorter presented the following paper on Geological 

 Revolutions : 



GEOLOGICAL REVOLUTIONS. 



There are many physical changes constantly going on around us 

 of which the cause is apparent to the most careless observer. If you 

 see a fresh bed of sand and gravel in the bed of a river, you do not 

 hesitate to conclude that it was deposited there by the last flooding of 

 the stream. If you observe that this fresh deposit overlaps an older 

 deposit of the same material on which young willows and cottonwoods 

 have started to grow, you conclude at once that this older bed of gravel 

 also had the same origin, by a flooding of the stream of older date. 

 Back of this still, you may trace evidences of floodings of still older 

 date. Now, in forming these conclusions concerning the natural origin 

 of these beds of sand and gravel, you have taken the first steps in 

 geological reasoning. You account for these beds of river-drift through 

 known causes that are familiar to your observation. 



Again, when you see the little rivulet with every shower of rain 

 wearing its channel deeper and deeper, you do not hesitate to conclude 

 that this little streamlet has made for itself the channel in which it 

 flows. You extend your observation to larger streams, where you see 

 the'same phenomena on a larger scale. From the little streamlet to the 

 majestic river, you can not doubt but the valleys through which they 

 flow have been worn to their present condition l3y the abrading action 

 of water. 



And finally, you observe that the whole surface of the country is 

 more or less water-worn into ravines, and natural drains, by which sur- 

 face water is conveyed to larger rivers, and thus to the ocean. You at 

 once conclude that all these ravines and valleys have been worn to their 

 present condition by the gradual action of water in finding its way to 

 the ocean — in short, by such causes as you see constantly in operation. 



Thus it is in all geological conclusions. A long series of observa- 

 tions, with a diligent study of the physical changes constantly going on, 

 and a careful comparison between such phenomena and the various 

 changes revealed through the rocky crust of the earth, have gradually 

 resulted in the conclusion, that all the geological revolutions of the 

 past ages have been effected through such known agencies as are in 

 operation at the present time. 



Now, at first thought this seems impossible. But the more we 

 study the physical changes constantly in operation, the more compre- 

 hensive the whole subject becomes. 



Careful observations have revealed the fact that the earth's surface, 

 that seems so firm and substantial, is not really so ; but is subject to 

 slow oscillations or changes of level ; that in some localities the land is 

 slowly subsiding, while other sections are being gradually elevated. 



